package org.apache.lucene.index;

/**
 * Provides access to stored term vector of
 * a document field.
 */
public interface TermFreqVector {
  /**
   * @return The field this vector is associated with.
   */
  public String getField();

  /**
   * @return The number of terms in the term vector.
   */
  public int size();

  /**
   * @return An Array of term texts in ascending order.
   */
  public String[] getTerms();


  /**
   * Array of term frequencies. Locations of the array correspond one to one
   * to the terms in the array obtained from <code>getTerms</code>
   * method. Each location in the array contains the number of times this
   * term occurs in the document or the document field.
   */
  public int[] getTermFrequencies();


  /**
   * Return an index in the term numbers array returned from
   * <code>getTerms</code> at which the term with the specified
   * <code>term</code> appears. If this term does not appear in the array,
   * return -1.
   */
  public int indexOf(String term);


  /**
   * Just like <code>indexOf(int)</code> but searches for a number of terms
   * at the same time. Returns an array that has the same size as the number
   * of terms searched for, each slot containing the result of searching for
   * that term number.
   *
   * @param terms array containing terms to look for
   * @param start index in the array where the list of terms starts
   * @param len   the number of terms in the list
   */
  public int[] indexesOf(String[] terms, int start, int len);

}
